A model of the neutral transport in tokamaks has been developed suitable for a one-dimensional transport code, TASK/TX. The model consists of the one-dimensional diffusion equations for slow, thermal and halo neutrals, which are simultaneously solved together with two-fluid equations and Maxwell’s equation. The behavior of the slow neutrals is easily modelled by a one-dimensional diffusion equa...

Nuclear magnetic resonance (NMR) may be used for monitoring temperature changes within samples based on measurements of relaxation times, the diffusion coefficient of liquids, proton resonance frequency or phase shifts. Such methods may be extended to the explicit measurement of the thermal diffusivity of materials by NMR imaging. A method based on measuring nuclear spin phase shifts or changes...

In this paper, thermal mixing characteristics of two miscible fluids in a T-shaped microchannel are investigated theoretically, experimentally, and numerically. Thermal mixing processes in a T-shaped microchannel are divided into two zones, consisting of a T-junction and a mixing channel. An analytical two-dimensional model was first built to describe the heat transfer processes in the mixing c...

Microfluidic devices that reduce evaporative loss during thermal bioreactions such as PCR without microvalves have been developed by relying on the principle of diffusion-limited evaporation. Both theoretical and experimental results demonstrate that the sample evaporative loss can be reduced by more than 20 times using long narrow diffusion channels on both sides of the reaction region. In ord...

We compute the thermal conductivity and diffusion coefficient of supercritical carbon dioxide along the 313 K isotherm using non-equilibrium molecular dynamics. Comparisons are made with experiment at four densities corresponding to pressures of 30, 70, 200 and 500 bar. Two intermolecular potential models for carbon dioxide are compared. INTRODUCTION In a previous paper (Wang and Cummings, 1988...

We studied experimentally a new phenomenon of turbulent thermal diffusion of particles which can cause formation of the large-scale aerosol layers in the vicinity of the atmospheric temperature inversions. This phenomenon was detected experimentally in oscillating grids turbulence in air flow. Three measurement techniques were used to study turbulent thermal diffusion in strongly inhomogeneous ...